diff --git a/tests/unit/test_client.py b/tests/unit/test_client.py
index 909823ee..85ac25f7 100644
--- a/tests/unit/test_client.py
+++ b/tests/unit/test_client.py
@@ -130,8 +130,8 @@ def assert_headers(headers):
         assert headers[constants.HEADER_CATALOG] == catalog
         assert headers[constants.HEADER_SCHEMA] == schema
         assert headers[constants.HEADER_SOURCE] == source
-        assert headers[constants.HEADER_USER] == user
-        assert headers[constants.HEADER_AUTHORIZATION_USER] == authorization_user
+        assert headers[constants.HEADER_ORIGINAL_USER] == user
+        assert headers[constants.HEADER_USER] == authorization_user
         assert headers[constants.HEADER_SESSION] == ""
         assert headers[constants.HEADER_TRANSACTION] is None
         assert headers[constants.HEADER_TIMEZONE] == timezone
diff --git a/trino/auth.py b/trino/auth.py
index 306539f0..783d0f5e 100644
--- a/trino/auth.py
+++ b/trino/auth.py
@@ -34,6 +34,7 @@
 
 import trino.logging
 from trino import exceptions
+from trino.constants import HEADER_ORIGINAL_USER
 from trino.constants import HEADER_USER
 from trino.constants import MAX_NT_PASSWORD_SIZE
 
@@ -552,7 +553,7 @@ def _determine_host(url: Optional[str]) -> Any:
 
     @staticmethod
     def _determine_user(headers: Mapping[Any, Any]) -> Optional[Any]:
-        return headers.get(HEADER_USER)
+        return headers.get(HEADER_ORIGINAL_USER, headers.get(HEADER_USER))
 
     @staticmethod
     def _construct_cache_key(host: Optional[str], user: Optional[str]) -> Optional[str]:
diff --git a/trino/client.py b/trino/client.py
index 7cc1f0f2..cf8ec9d1 100644
--- a/trino/client.py
+++ b/trino/client.py
@@ -511,8 +511,11 @@ def http_headers(self) -> CaseInsensitiveDict[str]:
         headers[constants.HEADER_CATALOG] = self._client_session.catalog
         headers[constants.HEADER_SCHEMA] = self._client_session.schema
         headers[constants.HEADER_SOURCE] = self._client_session.source
-        headers[constants.HEADER_USER] = self._client_session.user
-        headers[constants.HEADER_AUTHORIZATION_USER] = self._client_session.authorization_user
+        if self._client_session.authorization_user is not None:
+            headers[constants.HEADER_ORIGINAL_USER] = self._client_session.user
+            headers[constants.HEADER_USER] = self._client_session.authorization_user
+        else:
+            headers[constants.HEADER_USER] = self._client_session.user
         headers[constants.HEADER_TIMEZONE] = self._client_session.timezone
         if self._client_session.encoding is None:
             pass
diff --git a/trino/constants.py b/trino/constants.py
index 46b6e9ec..b136aaaf 100644
--- a/trino/constants.py
+++ b/trino/constants.py
@@ -33,6 +33,7 @@
 HEADER_SCHEMA = "X-Trino-Schema"
 HEADER_SOURCE = "X-Trino-Source"
 HEADER_USER = "X-Trino-User"
+HEADER_ORIGINAL_USER = "X-Trino-Original-User"
 HEADER_CLIENT_INFO = "X-Trino-Client-Info"
 HEADER_CLIENT_TAGS = "X-Trino-Client-Tags"
 HEADER_EXTRA_CREDENTIAL = "X-Trino-Extra-Credential"
@@ -61,7 +62,6 @@
 CLIENT_CAPABILITY_SESSION_AUTHORIZATION = "SESSION_AUTHORIZATION"
 CLIENT_CAPABILITIES = ','.join([CLIENT_CAPABILITY_PARAMETRIC_DATETIME, CLIENT_CAPABILITY_SESSION_AUTHORIZATION])
 
-HEADER_AUTHORIZATION_USER = "X-Trino-Authorization-User"
 HEADER_SET_AUTHORIZATION_USER = "X-Trino-Set-Authorization-User"
 HEADER_RESET_AUTHORIZATION_USER = "X-Trino-Reset-Authorization-User"